Webopedia on Google+Webopedia on TwitterWebopedia on FacebookTech Bytes Blog
Main » TERM » B »

BIOS - basic input output system

(bī´ōs) BIOS is an acronym for basic input/output system, the built-in software that determines what a computer can do without accessing programs from a disk. The BIOS is an important part of any computer system. On personal computers (PCs), for example, the BIOS contains all the code required to control the keyboard, display screen, disk drives, serial communications, and a number of miscellaneous functions.

The ROM BIOS Explained

The BIOS is typically placed in a ROM chip that comes with the computer (it is often called a ROM BIOS). This ensures that the BIOS will always be available and will not be damaged by disk failures. It also makes it possible for a computer to boot itself. Because RAM is faster than ROM, though, many computer manufacturers design systems so that the BIOS is copied from ROM to RAM each time the computer is booted. This is known as shadowing.

Many modern PCs have a flash BIOS, which means that the BIOS has been recorded on a flash memory chip, which can be updated if necessary.

PC BIOS Standardization

The PC BIOS is fairly standardized, so all PCs are similar at this level (although there are different BIOS versions). Additional DOS functions are usually added through software modules. This means you can upgrade to a newer version of DOS without changing the BIOS.

Newer PC BIOSes that can handle Plug-and-Play (PnP) devices are known as PnP BIOSes, or PnP-aware BIOSes. These BIOSes are always implemented with flash memory rather than ROM.







TECH RESOURCES FROM OUR PARTNERS
LATEST ARTICLES
8 Agenda Apps to Help Students Stay Organized

Webopedia's student apps roundup will help you to better organize your class schedule and stay on top of assignments and homework. Read More »

List of Free Shorten URL Services

A URL shortener is a way to make a long Web address shorter. Try this list of free services. Read More »

Top 10 Tech Terms of 2015

The most popular Webopedia definitions of 2015. Read More »

STUDY GUIDES
The 7 Layers of the OSI Model

The Open System Interconnection (OSI) model defines a networking framework to implement protocols in seven layers. Use this handy guide to compare... Read More »

Computer Architecture Study Guide

This Webopedia  study guide describes the different parts of a computer system and their relations. Read More »

What Are Network Topologies?

Network Topology refers to layout of a network. How different nodes in a network are connected to each other and how they communicate is... Read More »